It’s tempting to dismiss the people who plan in cold blood the execution of 132 schoolchildren as sick, twisted minds beyond the pale of human comprehension.

But, dishearteningly, the Pakistani Taliban’s attack Tuesday on a Peshawar school—one of their bloodiest atrocities—was likely the result of a rational cost-benefit analysis. Its bottom line: in this business, barbarism pays.

This,...

RELATED VIDEO

Pakistan Taliban: School Massacre Was Act of Revenge

The Pakistani Taliban claimed that Tuesday's deadly attack on a school in Peshawar was revenge for the Pakistani Army's operations to clear militants from the tribal area of Waziristan. Photo: AP